The "sha1sum" command:

Usage: fossil sha1sum FILE...
Compute an SHA1 checksum of all files named on the command-line.
If a file is named "-" then take its content from standard input.
Options:
-h, --dereference If FILE is a symbolic link, compute the hash
on the object that the link points to. Normally,
the hash is over the name of the object that
the link points to.